{{ $s := . }}
<div class="stack-diagram">
  {{ range $i, $l := $s.layers }}
  <div class="layer">
    <span class="layer-num">{{ printf "%02d" (add $i 1) }}</span>
    <h4>{{ $l.title }}</h4>
    <p>{{ $l.body }}</p>
  </div>
  {{ end }}
</div>
{{ with $s.spineLabel }}<p class="mcp-spine">{{ . }}</p>{{ end }}